Oakland A's Pitcher Trevor Cahill's Dramatic Improvement

It was pretty well known around here last season that I was not a fan of A's righthander Trevor Cahill.

That wasn't so much because I didn't think the former top prospect had great potential. It was more due to the fact that Cahill wasn't performing well and had completely ditched his best pitch, a big curveball.

Cahill throws five pitches: a four-seamer in the low-90's, a two-seamer around 90 with unbelievable movement, a low-80's changeup with excellent movement, the big curve, and a slider.

Last season, he essentially became a two-pitch pitcher, using the two-seam fastball and the changeup.

It didn't work.

Cahill had a respectable 4.63 ERA, but his FIP was 5.33, he struck out just 90 batters, and he allowed a horrific 27 homers.

Cahill's struggles showed one thing: major league hitters can hit pitches with excellent movement if they know the ball is simply going to move down and to the right each pitch. Cahill didn't understand that, and he just went fastball-changeup. He used his two breaking pitches just 10% of the time combined, and decreased their usage as the season went on.

Cahill entered the 2010 spring with a lot to prove. I was hoping he'd rededicate himself to his curveball, which scouts had praised as his best pitch while he was in the minors. I figured his hesitancy to throw the curve (just 2.7% usage in 2009) was the reason for his ineffectiveness.

Instead, Cahill announced that he had ditched his old curveball entirely and was working on a new curveball with a different grip.

Groan.

Cahill spent the spring trying to work on the pitch, but couldn't do enough to win a rotation spot over five more deserving pitchers. He was on the DL to open the year and went to Triple-A when he was healthy.

Soon enough, after just two starts there, the injury bug hit the A's, and they recalled Cahill.

Hoping to see this new curve in action, I was checking the pitch classifications for each pitch he threw in his first start.

He threw two curves and was was terrible as usual, allowing eight runs (six earned) in five innings, three homers allowed, and just three strikeouts.

In the next game, Cahill threw just three curves, and gutted through five decent innings.

His third outing saw five curves, and 5 2/3 passable innings.

And then, in his fourth start, Cahill unleashed the pitch, throwing it eighteen times. That start was his first quality start of the year, seven strong innings against the Angels on May 16.

Ever since then, Cahill's been throwing the curve 10-20 times a game. He uses it once every eight or nine pitches.

Trevor Cahill is 8-2 with a 2.74 ERA.

The new curve Cahill throws has four more inches of vertical break and 4.5 more of horizontal break than the old one, so it certainly looks like a wise decision to go to this version.

More importantly, however, the curve, along with a revamped, bigger slider give Cahill weapons that break to the left. Batters can no longer sit on the two-seamer/changeup combo because the curve and slider are very good pitches.

So the big change in his performance is not that the curve functions as Cahill's out pitch (although it can), it's that it makes his fastball and changeup better out pitches.

His strikeout rate has shot up over 1.5 K/9 to a passable 6.15, way up from the abysmal 4.53 of last season. Cahill's increased fastball effectiveness has contributed to an increase in his groundball rate as well. He now generates grounders on 54.3% of opposing contact, up from 47.8% last year. He's also allowed just five homers in his last 77 innings after allowing 27 last year and three in his first start this season.

Finally, Trevor Cahill has arrived. And thankfully, he's got more than two pitches.